04 225 DI carbon arc's on plugs

[sushi520vx]

2004 225 DI HO E225FHLSRM 280hrs
Been getting some carbon tracks or arc's on my plugs. Its between the electrode and the ground. Its been an ongoing problem for a few years. Ive installed the Etec plugs and T-stats. I havnt really been keeping track of which cyl(s) its been happening too. Is this from being too rich? Last yrs fuel? T-stat not closing and running cool? EMM need to be checked for updated software? Dirty injector(s)?

[JoePA]

Does the carbon cause the plug to short out? This happens on my 04 250 on the bottom cylinders mostly. I too have upgraded the plugs and t stats to Etec and it still happens. Decarb the engine at least twice as this has helped.

[sushi520vx]

Does the carbon cause the plug to short out? This happens on my 04 250 on the bottom cylinders mostly. I too have upgraded the plugs and t stats to Etec and it still happens. Decarb the engine at least twice as this has helped.

Not sure if it "shorts out" but if defiantly runs a bit rough. A solid piece of carbon. And I do think when its happened, it was the lower cyl's. This time it was middle starboard....(#5?). I have done a decarb a few yrs back and not much came out. I really havent put many hrs on since. I do run XD 100 which is supposed to help with carbon. I should do another decarb and see what happens.

[SEAHORSE]

If you haven't already, install 5005440 thermostats for better idle combustion, and check the cylinder head temps.

Do 2 decarbon procedures with Engine Tuner and use Carbon Guard for a tank or two of fuel.

[sushi520vx]

If you haven't already, install 5005440 thermostats for better idle combustion, and check the cylinder head temps.

Do 2 decarbon procedures with Engine Tuner and use Carbon Guard for a tank or two of fuel.

Thank you.
I will definitely do it and Im sure it will solve this issue.

[jcddllc]

Thanks for this thread, Ive been having the same issues for a while now and am going to swap the thermostats. While searching online for the 5005440 thermostats, several brands etc show up (brass vs stainless, etc). Are all these basically the same or should I steer away from any in particular?
https://www.amazon.com/5005440-83307...s%2C172&sr=8-3

Thanks

[SEAHORSE]

Factory thermostats are stainless steel

[ChampioNman]

Factory thermostats are stainless steel

Silly man! No one ever uses what should be used everyone want's cheap and quick. Nor do many support their local dealer.

[SEAHORSE]

Is that why you have cardboard and plastic thermostats ?

[ChampioNman]

Is that why you have cardboard and plastic thermostats ?

Naw, I use fender washers.

[jcddllc]

306EEF69-DB2D-4C23-80CA-E9EACFAC91E2.jpegAE81DB48-3EB4-49B1-8AA2-E2851FEDFF02.jpegOk gents. I tested the temp on my block and the port side was quite a bit cooler that starboard. I pulled out the thermostats hoping to find one stuck open but they were not. I’ll go ahead and order the newer thermostats, but is there any other reason for these low temps? Engine is e150fplsrs. I let it idle around 10 minutes to take temps.
thanks for any help.

[SEAHORSE]

Also inspect the pressure relief valve on top of the powerhead. It is sometimes known as a "blow off" valve. Any cooling water leakage past the plunger and seal can keep the engine at idle and low speeds from warming up properly.

[jcddllc]

Thanks for the tip. I pulled out pressure relief valve it looked ok as far as I could tell. What would I look for to know if its not working properly.
thanks for your help.

[SEAHORSE]

Glue in place the rubber seal for the plunger.